Blair McDougall, Better Together campaign director, said he was "humbled" by the level of financial support the campaign had attracted.

Blair Jenkins, Yes Scotland chief executive, said their "massive grassroots support" had been "overwhelming in its generosity" when it came to donations.

The Electoral Commission on Tuesday released the first of four pre-referendum reports detailing major donations made to official registered campaigners.

The body outlined all donations over £7,500 made to registered campaigners between 18 December 2013 to 26 June 2014. Smaller gifts were not included.

Better Together was found to have been given £2,406,475 in that period – more than twice as much as Yes Scotland's £1,160,000.

The pro-UK campaign group achieved that total thanks in part to gifts from major Scottish landowners and businessmen.

Ardverikie Estate Limited, which manages the estate featured in the BBC series Monarch of the Glen and the film Mrs. Brown, gave Better Together £10,000.

The Earl of Seafield, who owns two Highlands estates, donated £100,000, while the company that manages the estates and business interests of the Duke of Buccleuch and his family gave £25,000.

As well as JK Rowling's £1 million – the biggest donation to Better Together – the group also received £200,000 from Christopher Sansom, an eminent crime writer.

Gretna Green Ltd, a family business founded in 1886 which helps plan weddings, gave £10,000. Other donors included Bruno Schroder, a businessman estimated to be worth billions of pounds, Andrew Fraser, a stockbroker, and Sir David Garrard, a property developer.

Yes Scotland received £1 million from Colin and Chris Weir, the couple that scooped £161 million on the EuroMillions lottery in 2011.

The pro-independence campaign also received £10,000 from Walt Hopkins, a consultant whose website says he "inspires people to take their dreams seriously".

In terms of the other campaign groups, Business for Scotland were found to have been given £199,120, Christians for Independence £100,000, No Borders Campaign £75,000 and Mr Angus MacDonald £25,000.

Mr McDougall of Better Together said: "We are humbled by the level of financial support that our campaign has been able to attract.

He said the figures "do not paint the full picture of the generosity" of Scots towards the campaign, saying the group had raised £4 million in this period when thousands of smaller donations were included.

"What these figures tell us is that the Nationalists simply don't have a broad base of support," Mr McDougall said.

Mr Jenkins said some 10,705 people had given nearly £194,173 in the two months since Yes Scotland declared its running total in May.

"We still have a long way to go and hope that our supporters continue to help fund us to take the campaign over the finishing line with a resounding Yes vote on September 18," Mr Jenkins said.